The Product Rule of Exponents states that when you multiply two powers with the same base, you can add their exponents. The rule can be expressed as:
\[ a^m \times a^n = a^{m+n} \]
In your case, you have \(3^5\) and \(3^7\), which both have the same base of 3.
Using the Product Rule:
\[ 3^5 \times 3^7 = 3^{5+7} \]
Now, add the exponents:
\[ 5 + 7 = 12 \]
So, we can simplify:
\[ 3^5 \times 3^7 = 3^{12} \]
Therefore, the simplified expression is:
\[ 3^{12} \]